mcs/mcs/enum.cs

   1 //
   2 // enum.cs: Enum handling.
   3 //
   4 // Author: Miguel de Icaza (miguel@gnu.org)
   5 //         Ravi Pratap     (ravi@ximian.com)
   6 //
   7 // Licensed under the terms of the GNU GPL
   8 //
   9 // (C) 2001 Ximian, Inc (http://www.ximian.com)
  10 //
  11
  12 using System;
  13 using System.Collections;
  14 using System.Reflection;
  15 using System.Reflection.Emit;
  16 using System.Globalization;
  17
  18 namespace Mono.CSharp {
  19
  20         class EnumMember: MemberCore {
  21                 static string[] attribute_targets = new string [] { "field" };
  22
  23                 Enum parent_enum;
  24                 public FieldBuilder builder;
  25                 internal readonly Expression Type;
  26
  27                 public EnumMember (Enum parent_enum, Expression expr, string name,
  28                                    Location loc, Attributes attrs):
  29                         base (null, new MemberName (name), attrs, loc)
  30                 {
  31                         this.parent_enum = parent_enum;
  32                         this.ModFlags = parent_enum.ModFlags;
  33                         this.Type = expr;
  34                 }
  35
  36                 public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
  37                 {
  38                         if (a.Type == TypeManager.marshal_as_attr_type) {
  39                                 UnmanagedMarshal marshal = a.GetMarshal (this);
  40                                 if (marshal != null) {
  41                                         builder.SetMarshal (marshal);
  42                                 }
  43                                 return;
  44                         }
  45
  46                         if (a.Type.IsSubclassOf (TypeManager.security_attr_type)) {
  47                                 a.Error_InvalidSecurityParent ();
  48                                 return;
  49                         }
  50
  51                         builder.SetCustomAttribute (cb);
  52                 }
  53
  54                 public override AttributeTargets AttributeTargets {
  55                         get {
  56                                 return AttributeTargets.Field;
  57                         }
  58                 }
  59
  60                 public void DefineMember (TypeBuilder tb)
  61                 {
  62                         FieldAttributes attr = FieldAttributes.Public | FieldAttributes.Static
  63                                 | FieldAttributes.Literal;
  64
  65                         builder = tb.DefineField (Name, tb, attr);
  66                 }
  67
  68                 public override bool Define ()
  69                 {
  70                         throw new NotImplementedException ();
  71                 }
  72
  73                 public void Emit (EmitContext ec)
  74                 {
  75                         if (OptAttributes != null)
  76                                 OptAttributes.Emit (ec, this);
  77
  78                         Emit ();
  79                 }
  80
  81                 public override string GetSignatureForError()
  82                 {
  83                         return String.Concat (parent_enum.GetSignatureForError (), '.', base.GetSignatureForError ());
  84                 }
  85
  86                 public override string[] ValidAttributeTargets {
  87                         get {
  88                                 return attribute_targets;
  89                         }
  90                 }
  91
  92                 protected override bool VerifyClsCompliance(DeclSpace ds)
  93                 {
  94                         // Because parent is TypeContainer and we have only DeclSpace parent.
  95                         // Parameter replacing is required
  96                         return base.VerifyClsCompliance (parent_enum);
  97                 }
  98
  99                 // There is no base type
 100                 protected override void VerifyObsoleteAttribute()
 101                 {
 102                 }
 103
 104                 public override string DocCommentHeader {
 105                         get { return "F:"; }
 106                 }
 107         }
 108
 109         /// <summary>
 110         ///   Enumeration container
 111         /// </summary>
 112         public class Enum : DeclSpace {
 113                 public ArrayList ordered_enums;
 114
 115                 public Expression BaseType;
 116
 117                 public Type UnderlyingType;
 118
 119                 Hashtable member_to_location;
 120
 121                 //
 122                 // This is for members that have been defined
 123                 //
 124                 Hashtable member_to_value;
 125
 126                 //
 127                 // This is used to mark members we're currently defining
 128                 //
 129                 Hashtable in_transit;
 130
 131                 ArrayList field_builders;
 132
 133                 public const int AllowedModifiers =
 134                         Modifiers.NEW |
 135                         Modifiers.PUBLIC |
 136                         Modifiers.PROTECTED |
 137                         Modifiers.INTERNAL |
 138                         Modifiers.PRIVATE;
 139
 140                 public Enum (NamespaceEntry ns, TypeContainer parent, Expression type,
 141                              int mod_flags, MemberName name, Attributes attrs, Location l)
 142                         : base (ns, parent, name, attrs, l)
 143                 {
 144                         this.BaseType = type;
 145                         ModFlags = Modifiers.Check (AllowedModifiers, mod_flags,
 146                                                     IsTopLevel ? Modifiers.INTERNAL : Modifiers.PRIVATE, l);
 147
 148                         ordered_enums = new ArrayList ();
 149                         member_to_location = new Hashtable ();
 150                         member_to_value = new Hashtable ();
 151                         in_transit = new Hashtable ();
 152                         field_builders = new ArrayList ();
 153                 }
 154
 155                 /// <summary>
 156                 ///   Adds @name to the enumeration space, with @expr
 157                 ///   being its definition.
 158                 /// </summary>
 159                 public void AddEnumMember (string name, Expression expr, Location loc, Attributes opt_attrs, string documentation)
 160                 {
 161                         if (name == "value__") {
 162                                 Report.Error (76, loc, "An item in an enumeration can't have an identifier `value__'");
 163                                 return;
 164                         }
 165
 166                         EnumMember em = new EnumMember (this, expr, name, loc, opt_attrs);
 167                         em.DocComment = documentation;
 168                         if (!AddToContainer (em, name))
 169                                 return;
 170
 171
 172                         // TODO: can be almost deleted
 173                         ordered_enums.Add (name);
 174                         member_to_location.Add (name, loc);
 175                 }
 176
 177                 public override TypeBuilder DefineType ()
 178                 {
 179                         if (TypeBuilder != null)
 180                                 return TypeBuilder;
 181
 182                         ec = new EmitContext (this, this, Location, null, null, ModFlags, false);
 183                         ec.InEnumContext = true;
 184
 185                         if (!(BaseType is TypeLookupExpression)) {
 186                                 Report.Error (1008, Location,
 187                                               "Type byte, sbyte, short, ushort, int, uint, " +
 188                                               "long, or ulong expected (got: `{0}')", BaseType);
 189                                 return null;
 190                         }
 191
 192                         TypeExpr ute = ResolveBaseTypeExpr (BaseType, false, Location);
 193                         UnderlyingType = ute.Type;
 194
 195                         if (UnderlyingType != TypeManager.int32_type &&
 196                             UnderlyingType != TypeManager.uint32_type &&
 197                             UnderlyingType != TypeManager.int64_type &&
 198                             UnderlyingType != TypeManager.uint64_type &&
 199                             UnderlyingType != TypeManager.short_type &&
 200                             UnderlyingType != TypeManager.ushort_type &&
 201                             UnderlyingType != TypeManager.byte_type  &&
 202                             UnderlyingType != TypeManager.sbyte_type) {
 203                                 Report.Error (1008, Location,
 204                                               "Type byte, sbyte, short, ushort, int, uint, " +
 205                                               "long, or ulong expected (got: " +
 206                                               TypeManager.CSharpName (UnderlyingType) + ")");
 207                                 return null;
 208                         }
 209
 210                         if (IsTopLevel) {
 211                                 if (TypeManager.NamespaceClash (Name, Location))
 212                                         return null;
 213
 214                                 ModuleBuilder builder = CodeGen.Module.Builder;
 215
 216                                 TypeBuilder = builder.DefineType (Name, TypeAttr, TypeManager.enum_type);
 217                         } else {
 218                                 TypeBuilder builder = Parent.TypeBuilder;
 219
 220                                 TypeBuilder = builder.DefineNestedType (
 221                                         Basename, TypeAttr, TypeManager.enum_type);
 222                         }
 223
 224                         ec.ContainerType = TypeBuilder;
 225
 226                         //
 227                         // Call MapToInternalType for corlib
 228                         //
 229                         TypeBuilder.DefineField ("value__", UnderlyingType,
 230                                                  FieldAttributes.Public | FieldAttributes.SpecialName
 231                                                  | FieldAttributes.RTSpecialName);
 232
 233                         TypeManager.AddEnumType (Name, TypeBuilder, this);
 234
 235                         return TypeBuilder;
 236                 }
 237
 238                 bool IsValidEnumConstant (Expression e)
 239                 {
 240                         if (!(e is Constant))
 241                                 return false;
 242
 243                         if (e is IntConstant || e is UIntConstant || e is LongConstant ||
 244                             e is ByteConstant || e is SByteConstant || e is ShortConstant ||
 245                             e is UShortConstant || e is ULongConstant || e is EnumConstant ||
 246                             e is CharConstant)
 247                                 return true;
 248                         else
 249                                 return false;
 250                 }
 251
 252                 object GetNextDefaultValue (object default_value)
 253                 {
 254                         if (UnderlyingType == TypeManager.int32_type) {
 255                                 int i = (int) default_value;
 256
 257                                 if (i < System.Int32.MaxValue)
 258                                         return ++i;
 259                                 else
 260                                         return null;
 261                         } else if (UnderlyingType == TypeManager.uint32_type) {
 262                                 uint i = (uint) default_value;
 263
 264                                 if (i < System.UInt32.MaxValue)
 265                                         return ++i;
 266                                 else
 267                                         return null;
 268                         } else if (UnderlyingType == TypeManager.int64_type) {
 269                                 long i = (long) default_value;
 270
 271                                 if (i < System.Int64.MaxValue)
 272                                         return ++i;
 273                                 else
 274                                         return null;
 275                         } else if (UnderlyingType == TypeManager.uint64_type) {
 276                                 ulong i = (ulong) default_value;
 277
 278                                 if (i < System.UInt64.MaxValue)
 279                                         return ++i;
 280                                 else
 281                                         return null;
 282                         } else if (UnderlyingType == TypeManager.short_type) {
 283                                 short i = (short) default_value;
 284
 285                                 if (i < System.Int16.MaxValue)
 286                                         return ++i;
 287                                 else
 288                                         return null;
 289                         } else if (UnderlyingType == TypeManager.ushort_type) {
 290                                 ushort i = (ushort) default_value;
 291
 292                                 if (i < System.UInt16.MaxValue)
 293                                         return ++i;
 294                                 else
 295                                         return null;
 296                         } else if (UnderlyingType == TypeManager.byte_type) {
 297                                 byte i = (byte) default_value;
 298
 299                                 if (i < System.Byte.MaxValue)
 300                                         return ++i;
 301                                 else
 302                                         return null;
 303                         } else if (UnderlyingType == TypeManager.sbyte_type) {
 304                                 sbyte i = (sbyte) default_value;
 305
 306                                 if (i < System.SByte.MaxValue)
 307                                         return ++i;
 308                                 else
 309                                         return null;
 310                         }
 311
 312                         return null;
 313                 }
 314
 315                 void Error_ConstantValueCannotBeConverted (object val, Location loc)
 316                 {
 317                         if (val is Constant)
 318                                 Report.Error (31, loc, "Constant value '" + ((Constant) val).AsString () +
 319                                               "' cannot be converted" +
 320                                               " to a " + TypeManager.CSharpName (UnderlyingType));
 321                         else
 322                                 Report.Error (31, loc, "Constant value '" + val +
 323                                               "' cannot be converted" +
 324                                               " to a " + TypeManager.CSharpName (UnderlyingType));
 325                         return;
 326                 }
 327
 328                 /// <summary>
 329                 ///  Determines if a standard implicit conversion exists from
 330                 ///  expr_type to target_type
 331                 /// </summary>
 332                 public static bool ImplicitConversionExists (Type expr_type, Type target_type)
 333                 {
 334                         expr_type = TypeManager.TypeToCoreType (expr_type);
 335
 336                         if (expr_type == TypeManager.void_type)
 337                                 return false;
 338
 339                         if (expr_type == target_type)
 340                                 return true;
 341
 342                         // First numeric conversions
 343
 344                         if (expr_type == TypeManager.sbyte_type){
 345                                 //
 346                                 // From sbyte to short, int, long, float, double.
 347                                 //
 348                                 if ((target_type == TypeManager.int32_type) ||
 349                                     (target_type == TypeManager.int64_type) ||
 350                                     (target_type == TypeManager.double_type) ||
 351                                     (target_type == TypeManager.float_type)  ||
 352                                     (target_type == TypeManager.short_type) ||
 353                                     (target_type == TypeManager.decimal_type))
 354                                         return true;
 355
 356                         } else if (expr_type == TypeManager.byte_type){
 357                                 //
 358                                 // From byte to short, ushort, int, uint, long, ulong, float, double
 359                                 //
 360                                 if ((target_type == TypeManager.short_type) ||
 361                                     (target_type == TypeManager.ushort_type) ||
 362                                     (target_type == TypeManager.int32_type) ||
 363                                     (target_type == TypeManager.uint32_type) ||
 364                                     (target_type == TypeManager.uint64_type) ||
 365                                     (target_type == TypeManager.int64_type) ||
 366                                     (target_type == TypeManager.float_type) ||
 367                                     (target_type == TypeManager.double_type) ||
 368                                     (target_type == TypeManager.decimal_type))
 369                                         return true;
 370
 371                         } else if (expr_type == TypeManager.short_type){
 372                                 //
 373                                 // From short to int, long, float, double
 374                                 //
 375                                 if ((target_type == TypeManager.int32_type) ||
 376                                     (target_type == TypeManager.int64_type) ||
 377                                     (target_type == TypeManager.double_type) ||
 378                                     (target_type == TypeManager.float_type) ||
 379                                     (target_type == TypeManager.decimal_type))
 380                                         return true;
 381
 382                         } else if (expr_type == TypeManager.ushort_type){
 383                                 //
 384                                 // From ushort to int, uint, long, ulong, float, double
 385                                 //
 386                                 if ((target_type == TypeManager.uint32_type) ||
 387                                     (target_type == TypeManager.uint64_type) ||
 388                                     (target_type == TypeManager.int32_type) ||
 389                                     (target_type == TypeManager.int64_type) ||
 390                                     (target_type == TypeManager.double_type) ||
 391                                     (target_type == TypeManager.float_type) ||
 392                                     (target_type == TypeManager.decimal_type))
 393                                         return true;
 394
 395                         } else if (expr_type == TypeManager.int32_type){
 396                                 //
 397                                 // From int to long, float, double
 398                                 //
 399                                 if ((target_type == TypeManager.int64_type) ||
 400                                     (target_type == TypeManager.double_type) ||
 401                                     (target_type == TypeManager.float_type) ||
 402                                     (target_type == TypeManager.decimal_type))
 403                                         return true;
 404
 405                         } else if (expr_type == TypeManager.uint32_type){
 406                                 //
 407                                 // From uint to long, ulong, float, double
 408                                 //
 409                                 if ((target_type == TypeManager.int64_type) ||
 410                                     (target_type == TypeManager.uint64_type) ||
 411                                     (target_type == TypeManager.double_type) ||
 412                                     (target_type == TypeManager.float_type) ||
 413                                     (target_type == TypeManager.decimal_type))
 414                                         return true;
 415
 416                         } else if ((expr_type == TypeManager.uint64_type) ||
 417                                    (expr_type == TypeManager.int64_type)) {
 418                                 //
 419                                 // From long/ulong to float, double
 420                                 //
 421                                 if ((target_type == TypeManager.double_type) ||
 422                                     (target_type == TypeManager.float_type) ||
 423                                     (target_type == TypeManager.decimal_type))
 424                                         return true;
 425
 426                         } else if (expr_type == TypeManager.char_type){
 427                                 //
 428                                 // From char to ushort, int, uint, long, ulong, float, double
 429                                 //
 430                                 if ((target_type == TypeManager.ushort_type) ||
 431                                     (target_type == TypeManager.int32_type) ||
 432                                     (target_type == TypeManager.uint32_type) ||
 433                                     (target_type == TypeManager.uint64_type) ||
 434                                     (target_type == TypeManager.int64_type) ||
 435                                     (target_type == TypeManager.float_type) ||
 436                                     (target_type == TypeManager.double_type) ||
 437                                     (target_type == TypeManager.decimal_type))
 438                                         return true;
 439
 440                         } else if (expr_type == TypeManager.float_type){
 441                                 //
 442                                 // float to double
 443                                 //
 444                                 if (target_type == TypeManager.double_type)
 445                                         return true;
 446                         }
 447
 448                         return false;
 449                 }
 450
 451                 /// <summary>
 452                 ///  This is used to lookup the value of an enum member. If the member is undefined,
 453                 ///  it attempts to define it and return its value
 454                 /// </summary>
 455                 public object LookupEnumValue (string name, Location loc)
 456                 {
 457                         if (ec == null)
 458                                 Report.Error (-1, loc, "Enum.LookupEnumValue () called too soon");
 459
 460                         object default_value = null;
 461                         Constant c = null;
 462
 463                         default_value = member_to_value [name];
 464
 465                         if (default_value != null)
 466                                 return default_value;
 467
 468                         //
 469                         // This may happen if we're calling a method in System.Enum, for instance
 470                         // Enum.IsDefined().
 471                         //
 472                         if (!defined_names.Contains (name))
 473                                 return null;
 474
 475                         if (in_transit.Contains (name)) {
 476                                 Report.Error (110, loc, "The evaluation of the constant value for `" +
 477                                               Name + "." + name + "' involves a circular definition.");
 478                                 return null;
 479                         }
 480
 481                         //
 482                         // So if the above doesn't happen, we have a member that is undefined
 483                         // We now proceed to define it
 484                         //
 485                         Expression val = this [name];
 486
 487                         if (val == null) {
 488
 489                                 int idx = ordered_enums.IndexOf (name);
 490
 491                                 if (idx == 0)
 492                                         default_value = 0;
 493                                 else {
 494                                         for (int i = 0; i < idx; ++i) {
 495                                                 string n = (string) ordered_enums [i];
 496                                                 Location m_loc = (Mono.CSharp.Location)
 497                                                         member_to_location [n];
 498                                                 in_transit.Add (name, true);
 499                                                 default_value = LookupEnumValue (n, m_loc);
 500                                                 in_transit.Remove (name);
 501                                                 if (default_value == null)
 502                                                         return null;
 503                                         }
 504
 505                                         default_value = GetNextDefaultValue (default_value);
 506                                 }
 507
 508                         } else {
 509                                 in_transit.Add (name, true);
 510                                 val = val.Resolve (EmitContext);
 511                                 in_transit.Remove (name);
 512
 513                                 if (val == null)
 514                                         return null;
 515
 516                                 if (!IsValidEnumConstant (val)) {
 517                                         Report.Error (
 518                                                 1008, loc,
 519                                                 "Type byte, sbyte, short, ushort, int, uint, long, or " +
 520                                                 "ulong expected (have: " + val + ")");
 521                                         return null;
 522                                 }
 523
 524                                 c = (Constant) val;
 525                                 default_value = c.GetValue ();
 526
 527                                 if (default_value == null) {
 528                                         Error_ConstantValueCannotBeConverted (c, loc);
 529                                         return null;
 530                                 }
 531
 532                                 if (val is EnumConstant){
 533                                         Type etype = TypeManager.EnumToUnderlying (c.Type);
 534
 535                                         if (!ImplicitConversionExists (etype, UnderlyingType)){
 536                                                 Convert.Error_CannotImplicitConversion (
 537                                                         loc, c.Type, UnderlyingType);
 538                                                 return null;
 539                                         }
 540                                 }
 541                         }
 542
 543                         EnumMember em = (EnumMember) defined_names [name];
 544                         em.DefineMember (TypeBuilder);
 545
 546                         bool fail;
 547                         default_value = TypeManager.ChangeType (default_value, UnderlyingType, out fail);
 548                         if (fail){
 549                                 Error_ConstantValueCannotBeConverted (c, loc);
 550                                 return null;
 551                         }
 552
 553                         em.builder.SetConstant (default_value);
 554                         field_builders.Add (em.builder);
 555                         member_to_value [name] = default_value;
 556
 557                         if (!TypeManager.RegisterFieldValue (em.builder, default_value))
 558                                 return null;
 559
 560                         return default_value;
 561                 }
 562
 563                 public override bool DefineMembers (TypeContainer parent)
 564                 {
 565                         return true;
 566                 }
 567
 568                 public override bool Define ()
 569                 {
 570                         //
 571                         // If there was an error during DefineEnum, return
 572                         //
 573                         if (TypeBuilder == null)
 574                                 return false;
 575
 576                         if (ec == null)
 577                                 throw new InternalErrorException ("Enum.Define () called too soon");
 578
 579                         object default_value = 0;
 580
 581
 582                         foreach (string name in ordered_enums) {
 583                                 //
 584                                 // Have we already been defined, thanks to some cross-referencing ?
 585                                 //
 586                                 if (member_to_value.Contains (name))
 587                                         continue;
 588
 589                                 Location loc = (Mono.CSharp.Location) member_to_location [name];
 590
 591                                 if (this [name] != null) {
 592                                         default_value = LookupEnumValue (name, loc);
 593
 594                                         if (default_value == null)
 595                                                 return true;
 596                                 } else {
 597                                         if (name == "value__"){
 598                                                 Report.Error (76, loc, "The name `value__' is reserved for enumerations");
 599                                                 return false;
 600                                         }
 601
 602                                         EnumMember em = (EnumMember) defined_names [name];
 603
 604                                         em.DefineMember (TypeBuilder);
 605                                         FieldBuilder fb = em.builder;
 606
 607                                         if (default_value == null) {
 608                                            Report.Error (543, loc, "Enumerator value for '" + name + "' is too large to " +
 609                                                               "fit in its type");
 610                                                 return false;
 611                                         }
 612
 613                                         bool fail;
 614                                         default_value = TypeManager.ChangeType (default_value, UnderlyingType, out fail);
 615                                         if (fail){
 616                                                 Error_ConstantValueCannotBeConverted (default_value, loc);
 617                                                 return false;
 618                                         }
 619
 620                                         fb.SetConstant (default_value);
 621                                         field_builders.Add (fb);
 622                                         member_to_value [name] = default_value;
 623
 624                                         if (!TypeManager.RegisterFieldValue (fb, default_value))
 625                                                 return false;
 626                                 }
 627
 628                                 default_value = GetNextDefaultValue (default_value);
 629                         }
 630
 631                         return true;
 632                 }
 633
 634                 public override void Emit ()
 635                 {
 636                         if (OptAttributes != null) {
 637                                 OptAttributes.Emit (ec, this);
 638                         }
 639
 640                         foreach (EnumMember em in defined_names.Values) {
 641                                 em.Emit (ec);
 642                         }
 643
 644                         base.Emit ();
 645                 }
 646
 647                 void VerifyClsName ()
 648                 {
 649                         Hashtable ht = new Hashtable ();
 650                         foreach (string name in ordered_enums) {
 651                                 string locase = name.ToLower (System.Globalization.CultureInfo.InvariantCulture);
 652                                 if (!ht.Contains (locase)) {
 653                                         ht.Add (locase, defined_names [name]);
 654                                         continue;
 655                                 }
 656
 657                                 MemberCore conflict = (MemberCore)ht [locase];
 658                                 Report.SymbolRelatedToPreviousError (conflict);
 659                                 conflict = GetDefinition (name);
 660                                 Report.Error (3005, conflict.Location, "Identifier '{0}' differing only in case is not CLS-compliant", conflict.GetSignatureForError ());
 661                         }
 662                 }
 663
 664                 protected override bool VerifyClsCompliance (DeclSpace ds)
 665                 {
 666                         if (!base.VerifyClsCompliance (ds))
 667                                 return false;
 668
 669                         VerifyClsName ();
 670
 671                         if (!AttributeTester.IsClsCompliant (UnderlyingType)) {
 672                                 Report.Error (3009, Location, "'{0}': base type '{1}' is not CLS-compliant", GetSignatureForError (), TypeManager.CSharpName (UnderlyingType));
 673                         }
 674
 675                         return true;
 676                 }
 677
 678                 //
 679                 // IMemberFinder
 680                 //
 681                 public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
 682                                                         MemberFilter filter, object criteria)
 683                 {
 684                         ArrayList members = new ArrayList ();
 685
 686                         if ((mt & MemberTypes.Field) != 0) {
 687                                 if (criteria is string && member_to_value [criteria] == null) {
 688                                         LookupEnumValue ((string) criteria, Location.Null);
 689                                 }
 690
 691                                 foreach (FieldBuilder fb in field_builders)
 692                                         if (filter (fb, criteria) == true)
 693                                                 members.Add (fb);
 694                         }
 695
 696                         return new MemberList (members);
 697                 }
 698
 699                 public override MemberCache MemberCache {
 700                         get {
 701                                 return null;
 702                         }
 703                 }
 704
 705                 public ArrayList ValueNames {
 706                         get {
 707                                 return ordered_enums;
 708                         }
 709                 }
 710
 711                 // indexer
 712                 public Expression this [string name] {
 713                         get {
 714                                 return ((EnumMember) defined_names [name]).Type;
 715                         }
 716                 }
 717
 718                 public override AttributeTargets AttributeTargets {
 719                         get {
 720                                 return AttributeTargets.Enum;
 721                         }
 722                 }
 723
 724                 protected override TypeAttributes TypeAttr {
 725                         get {
 726                                 return Modifiers.TypeAttr (ModFlags, IsTopLevel) |
 727                                 TypeAttributes.Class | TypeAttributes.Sealed |
 728                                 base.TypeAttr;
 729                         }
 730                 }
 731
 732
 733                 protected override void VerifyObsoleteAttribute()
 734                 {
 735                         // UnderlyingType is never obsolete
 736                 }
 737
 738                 //
 739                 // Generates xml doc comments (if any), and if required,
 740                 // handle warning report.
 741                 //
 742                 internal override void GenerateDocComment (DeclSpace ds)
 743                 {
 744                         DocUtil.GenerateEnumDocComment (this, ds);
 745                 }
 746
 747                 //
 748                 //   Represents header string for documentation comment.
 749                 //
 750                 public override string DocCommentHeader {
 751                         get { return "T:"; }
 752                 }
 753         }
 754 }